At most respawn rates and dunjon depths, it would be impossible to clear all the levels at once, especially when entering one level often triggers the respawn of another level. Simply clearing each of the levels once is not that difficult.

You can easily just list a few suggestions of builds that work........

I'll start a new thread asking for suggestions of character (Hybrid) builds that work well, and I'll add these to the character creation page on my help site. I still haven't tried many of the hybrid combinations myself, so I'll need some help from players who've tried other builds.